Monday, March 06, 2006

If women were dressed like the men at the oscars,

Saturday, March 04, 2006

Pace vs Bounce - 2

In the previous post, I talked about pitches with good pace but not bounce. I gave Sabina park as an example.While the shiny Sabina park pitch, beacuse of its lesser friction, offers pace, I dint explain why the 'bounce' of this pitch is not steep.

The Sabina park pitch is hard; this means its coefficient of restitution is high. Then why no steep bounce? Curiously the reason for this is beacuse of its pace! Lets see why...

First, what do we mean by bounce? It is the angle (with the horizonatal) with which the ball rises after it hits the ground. Greater the angle, steeper the bounce.

Now consider two pitches A and B. Both the pitches have identical values of coefficient of restitution.But pitch A is faster (has lesser friction) than pitch B. Now suppose a bowler bowls identical balls (around the good-length area) with the same speed on two pitches.

Pitch B being slower pitch, reduces the horizontal component with which the ball leaves pitch B, much more compared to pitch A. This causes the ball in pitch B to rise at a greater angle, compared to pitch A. The slower the pitch, the greater the angle with which it rises!!

This means that sometimes (when the coefficient of restitution are the same) the faster pitch, has a less steeper bounce. (which is very non-intuitive).

Then why is there good correlation observed between pace and bounce in pitches around the world.This is beacuse there is a good observed correlation between coeffcient of restitution and the lack of friction in the pitch.

This explains why it is very awkward to play spin bowling in a tennis ball. Have you ever observed somebody driving "on the up" against slowly bowled tennis ball. I havent...People either go to the pitch of the ball or stay back and play against slow tennis ball bowling. This is because of the steepbounce at which the ball rises after it hits the ground. That is why this is called tennis-ball bounce.